1. Field of the Invention
The present invention relates to a tool coupling structure that is capable of obtaining secure locking function and rotate thing the sphere knob to a desired angle easily.
2. Description of the Prior Arts
As shown in FIGS. 1 and 2, a conventional tool coupling structure disclosed in TW Pat. No. 98201746 includes a shank 10, an operating member 20, and a limiting structure 30, wherein the shank 10 includes a polygonal sphere knob 12 and a peripheral side 13 disposed on one end thereof, and includes a driving end 11 driven by a driving device, and the sphere knob 12 includes an orifice mounted on a largest diameter portion thereof to receive a biasing element 15 pushed by a resilient element 14 so that the biasing element 15 moves to the orifice; the operating member 20 includes a polygonal cavity 21 fixed on one end thereof and an operating tool fitted on another end thereof, the cavity 21 includes a retaining recess 22 and an annular groove 23 secured on a suitable portion thereof, and includes an annular abutting rim 24 arranged around an opening of thereof. The sphere knob 12 is fitted to the cavity 21 of the operating member 20, and the limiting structure 30 is provided in the annular groove 23 so that the sphere knob 12 of the shank 10 is retained in the cavity 21, and the sphere head 12 moves between a first and a second positions. As illustrated in FIG. 2, when the shank 10 is pressed to move toward the first position, because the peripheral side 13 of the shank 10 is fitted to the annular abutting rim 24 of the operating member 20, the shank 10 and the operating member 20 are coupled together linearly so that the driving device actuates the tool directly. As shown in FIG. 3, when the shank 10 is pulled to be located at the second position, due to the peripheral side 13 of the shank 10 disengages from the annular abutting rim 24 of the operating member 20, the shank 10 swings relative to the operating member 20 along the sphere knob 12 to be rotated at an angle, hence the tool can be used in a narrow space. Referring further to FIG. 2, even though the limiting structure 30 is provided to prevent the sphere knob 12 of the shank 10 from disengaging from the cavity 21 of the operating member 20, when the shank 10 is located at the first position, the biasing element 15 abuts against a defining slot 22 of the cavity 21, however the biasing element 15 and the defining slot 22 can not provide secure positioning function, hence when user rotates the driving device, the shank 10 moves to the second position easily to cause a danger.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.